Swiss tennis champion Roger Federer will return to Perth next year to compete in the Hopman Cup but the cost of drawing him back to Western Australia remains a tightly-held secret.
While the world No.2 was in Perth for last year's cup, he posed for a selfie with a quokka on Rottnest Island, which went viral on social media and helped boost tourism to the holiday hotspot.
The state government refused at the time to say how much Federer was paid and remains tight-lipped, saying the sum is commercial-in-confidence.
Revealing the figure will compromise WA's ability to compete with other states to attract tourism drawcards like Federer, Tourism Minister Paul Papalia says.
"We can't reveal the amount we paid, obviously, because that would compromise our ability to not only get Roger or any other serious figure in the future in a similar fashion," Mr Papalia told reporters on Tuesday.
He said the McGowan government would "extract far greater value" than the Liberals, who got Federer to play beach tennis with former premier Colin Barnett and young fans on the shores of Cottesloe in 2016.
"When the leader of the opposition comes out in his whiny voice and says 'they've got to tell us how much they paid', you can say to him that we paid exactly the same amount that he did two years ago when he signed a confidentiality agreement," Mr Papalia said.
Federer's return in the New Year will be the 20-time grand slam singles champion's fifth time representing Switzerland at the mixed teams tennis tournament.